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species on the climate changeHIT LIST

Many forces – including habitat destruction and overfi shing – are already driving species to extinction, and for someclimate change is likely to prove the fi nal straw. Last December the International Union for Conservation of Nature(IUCN) published a study of the most at risk from global warming; seven of them are described below. Yet, as SimonStuart, Chair of IUCN’s Species Survival Commission, says, ‘Ordinary people are not powerless to stop these tragiclosses. They can cut down on their own CO2 emissions and voice their support for strong action by their governments tochange the dire climate prognosis we are currently facing.’

Clown fish

Clownfish were made famous by the fi lm Finding Nemo, but their real
lives are even stranger than fi ction. If the sole female in a group
dies, for example, the largest male of the group changes sex to allow
breeding to continue. They are also able to build immunity to a
particular sea anemone’s poison, live among the anemone’s tentacles and
lay their eggs beneath them, so that they are protected from predators.
When the eggs hatch, the larvae follow chemical signals in the water to
detect a suitable anemone for a new home. But as the oceans grow more
acid as they absorb more and more CO2 from the atmosphere, it is
increasingly diffi cult for the clownfi sh to detect these signals.

Koala

Koalas are fussy eaters: they will only consume the leaves of a few
dozen of the more than 600 species of gum trees. Eucalyptus leaves are
already poor in nutrients, and increased levels of CO2 have been shown
to reduce protein and increase levels of tannin, a chemical which makes
leaf proteins highly indigestible. Eating more, to try to make up for
reduced nutritional quality, would cause poorer digestion and a lower
uptake of nutrients. Alternatively, koalas may become even more choosy
about what gums they will eat and will have to travel further to fi nd
them, increasing the risk of being killed by dogs and cars; 4,000 a year
already die like this. Increased droughts and forest fi res will reduce
their food supplies even further.

Leatherback turtle

As the sands in which they lay their eggs warm up, leatherback turtles
will become more and more endangered. For, strangely, their temperature
determines the gender of the newborn and, as global warming increases,
the proportion of females to males will also grow, threatening the
stability of their populations. Rising temperatures will also affect
their staple food, jellyfi sh, which are generally found in cool,
nutrient-laden, upward-fl owing waters. And the more frequent and severe
storms brought by global warming will erode and degrade beaches,
causing turtle nests to be washed away in the short term, and reducing
the number of suitable nesting areas in the long run.

Emperor penguin

Emperor penguins depend on ice, both to live on as chicks before they fl
edge and to use as they moult. So they are particularly vulnerable to
the rising thermometer. Air temperatures on the west coast of the
Antarctic Peninsula, one of their main habitats, have risen by nearly
3°C over the past 50 years. If global temperatures rise by a further 2°C
all their colonies north of 70° (almost 40 per cent of the total) would
become unviable. Rising temperatures and thinning ice are also likely
to lead to more frequent incidences of icebergs colliding with penguin
colonies, as happened in 2001. And projected declines in pack ice are
likely to reduce populations of the krill they feed on, and that form
the base of much of the Antarctic food web

Quiver tree

The quiver tree – so called because San Bushmen hunters use it to make
quivers for their arrows – is Namibia’s national plant. Growing in the
desert, the tree’s pulpy, water-retentive wood yields drinking water and
makes dead trunks suitable for hollowing out to use as natural
refrigerators. Their bark can be used for building and their flowers
provide nectar to feed a range of insects, birds and even baboons. While
animal species can adapt to climate change by moving, plants including
trees are much less mobile and rely on animals to disperse their seeds.
But these are moving south, and so the northernmost trees are
increasingly vulnerable and large numbers have already died.

Arctic fox

One of the fi rst mammals to colonize Sweden and Finland following the last ice age, and now found as far west asAlaska
and as far east as Russia, the arctic fox gives birth to its young in
summer in complex underground dens that can host several generations.
The number of young born in each litter depends on how much food is
available, but many of the fox’s prey animals – including lemmings and
voles which rely on the insulation provided by snow to get them through
the winter – are suffering as a result of mild temperatures. Climate
change is also pushing the arctic fox’s greatest competitor and
predator, the red fox, to encroach upon its territory.

Staghorn coral

The 160 species of antler-shaped staghorn corals make up over 20 per
cent of the world’s coral. They depend on algae – which give them their
colour – for oxygen and nutrients. But as sea temperatures rise the
algae produce too much oxygen, which can poison the corals. So they
expel the colourful algae and become ‘bleached’, also losing the algae’s
life-giving assistance. If the waters resume their normal temperature
within a few weeks, there is hope that the corals will recover, but the
damage caused is not totally reversible and the colonies never return to
their full state of health. Already a fi fth of coral reefs worldwide
are damaged beyond repair.

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